A wolf was eating an animal it had killed. Suddenly, a small bone in the meat got stuck in his throat and he could not swallow it. Soon, he felt terrible pain in the throat, and ran up and down seeking for something to relieve the pain. He asked everyone he met to cure him. At last the wolf met the crane. The wolf said, "Please help me. I will give you what you want." The crane agreed to try and told the wolf to lie on its side and open its jaws as wide as it could. Then the crane put its long neck down the wolfs throat and got the bone out of its throat. Then the crane said, "Will you kindly give me the reward you promised?" The wolf grinned and showed his teeth and said, "Be content. you have put your head inside a wolf's mouth and taken it out again in safety; that was your reward." 
Gratitude and greed go not together. 